The background to the invention can be seen from Swedish patent application SE 0100830-9 with publication number SE 520871, with equivalence in U.S. Pat. No. 7,051,680. This publication shows an animal keeping installation having a floor, a tending device and a drive device for the tending device. The drive device acts upon the floor, which is driven by an animal, through movement, subjecting the floor to a dynamic load which causes an energy-absorbing device to absorb energy, which is later released and produces driving of the floor.
The said publication shows in one embodiment an energy storage through tensioning of a helical spring, which stored energy is used to drive a drive roll.
In another shown embodiment in this publication another type of energy storage in the form of a weight is shown, the potential energy of which is stored until an energy extraction is made and the potential energy is discharged so as to be stored again.
Further embodiments for energy storage comprising spring, tension cord and pendulum are indicated in the said publication.
Many of these drive devices require that the drive roll is connected to a ratchet wheel in the storage of energy, which ratchet wheel is released and driving of the floor is able to be initiated.
Each of these energy storage principles with drive devices requires a realized construction which is not shown in this publication. The construction can be realized in many different ways, but has proved difficult to realize in a simple, functionally reliable and cost-effective manner.
One problem is that the driving of the endless mat of the floor tends to skew the mat in relation to the drive roll, which means that the mat slides against mountings and bearings, which causes the mat to be torn to pieces and results in operating disturbances and breakdowns.